The present invention relates to allocation of resources in a communications network and more particularly to scheduling reservations for connections across a communications network.
A conventional communications network comprises a plurality of nodes, at which are provided node equipment, the nodes connected by a plurality of communications links, the links comprising link equipment. The node equipment may comprise, for example a personal computer or a telecommunications switch apparatus, and the links may comprise, for example a coaxial cable linking computers, or a terrestrial or atmospheric telecommunications link, such as an optical fiber link, microwave link or the like.
Such types of traffic carried by a network, such as that resulting from data communication is often of a bursty nature which means that shortxe2x80x9cburstsxe2x80x9d of high communication activity occur between longer periods of low or no network traffic. This kind of traffic leads to the network- being especially prone to overloading of link equipment. Further, at certain times of the day there is more likely to be a high volume of network traffic than at other times. For example, axe2x80x9cbusy hourxe2x80x9d occurs around 11.00 am of each weekday morning, and at around 2.00-3.00 pm each week day.
Conventional telecommunications networks operate by making connections between subscribers. A connection is a communications path between a source node and one or more destination nodes via a route across one or more network links. Certain usages of communications networks such as the carrying of voice conferencing communication traffic data or distance learning traffic data heavily utilize bitrate across a connection and can require point to multipoint or multipoint to multipoint connections. These types of usage can use a large proportion of the bitrate capacity of the links used by a connection. If traffic of one connection attempts to use the same link as traffic of another connection at the same time, this can result in individual link equipment being saturated leading to congestion on the network. In applications which are particularly sensitive to maintaining quality of service, for example the transfer of computer data, overloading of links leads to corruption of the data. For example, in an asynchronous transfer mode (ATM) communications network, overloading of node and link equipment produces loss of ATM cells of data. ATM cells are buffered at node equipment prior to transmitting over links. Where congestion occurs, buffers overfill and ATM cells are overwritten by newly arrived incoming cells. Traffic data contained in the overwritten cells is lost.
In particular, with the advent and increased availability of ATM communications systems, there is provided large amounts of bitrate which are available across a communications network. ATM systems are becoming increasingly available in access networks and are particularly suited to point to multipoint and multipoint to multipoint service types.
One object of the present invention is to schedule services across a communications network, where a nature of the service, eg such as its bitrate, data type and projected time of commencement are known in advance.
Another object of the present invention is to ensure that the network links have the necessary bitrate capacities to cope with transferring data without corrupting it.
According to a first aspect of the present invention there is provided a process for reserving a plurality of connections in a communications network, said process comprising the machine executable steps of:
inputting a plurality of connection requests describing a plurality of required connections, each said connection request specifying a predetermined time for said connection; and
reserving a plurality of connections across said communications network in response to said plurality of connection requests.
Preferably said step of reserving connections comprises, for each required connection;
searching for an available route for said connection; and
where an available route is found for said connection, reserving said route in advance of said predetermined time.
A schedule of connections with associated routes may comprise for example a schedule for a 24 hour day divided into one second intervals. The schedule of connections may be tailored to time intervals chosen to suit a required horizon or granularity suited to operation timescales and constraints.
Said reservations algorithm may be applied to all or some of said connection requests an indefinite number of times.
Preferably a said connection request specifies a required bitrate and said step of searching comprising searching for one or more routes having an available capacity capable of supporting said required bitrate.
Preferably the process comprises the step of, for each required connection, allocating capacity of a corresponding reserved route to said connection.
Said predetermined time may comprise a start time.
Preferably said process comprises the step of searching for a valid route for each requested connection from a list of all possible routes across said network.
Said process may comprise the step of constraining a search of all possible routes within operator defined constraint parameters.
Said process may comprise the step of searching for an available route by creating a list of a plurality of routes between a plurality of corresponding respective source nodes and destination nodes of said plurality of requested connections.
Said connection requests may be stored as a list of connection requests awaiting available routes.
The process may further comprise the step of storing a list of connection requests for which routes have been reserved.
The process may further comprise the step of displaying a list of connection requests which are awaiting available routes.
The process may further comprise the step of displaying a list of connection requests for which routes have been reserved.
Preferably the process comprises the step of displaying a plurality of display views of said reserved connections.
Said process may comprise the step of generating a network view showing node elements and link elements as a plurality of corresponding icons and visually displaying a route taken by a reserved connection on said network view.
Said process may further comprise the step of displaying a list of reserved connections, and for each said displayed reserved connection displaying a start time of the reserved connection. The process may comprise the step of displaying an end time of the reserved connection.
Said process may further comprise the step of displaying data describing parameters of a reserved connection, wherein said parameters are selected from the set a traffic type; a link data capacity; a route data capacity; a peak bitrate; an average bitrate; an estimated cell loss; a priority rating of a said connection.
Said process may further comprise the step of generating a display view of a said reserved connection, said view comprising a bar chart display displaying data representing a plurality of links on a first axis, and displaying data representing time on a second axis; wherein said data representing a plurality of said links comprises data representing utilization of said links.
Said process may further comprise the step of generating a display view displaying data describing a plurality of services carried on said reserved connections.
According to a second aspect of the present invention there is provided a network management apparatus for managing a communications network comprising a plurality of node elements and a plurality of link elements, wherein data communication services are carried over a plurality of end to end connections over said nodes and links, said apparatus comprising:
interface means for inputting a plurality of requests for connections across said network; and
means for reserving a plurality of connections across said communications network in response to said plurality of connection requests.
Preferably the network management apparatus further comprises:
display means for displaying a plurality of said reserved connections,
wherein said display means supports a plurality of display views of said reserved connections.
The network management apparatus may comprise display means supporting a plurality of display views, wherein a said view comprises a network view showing node elements and link elements as a plurality of corresponding icons; and means for visually displaying a route taken by a said reserved connection on said network view.
The network management apparatus may further comprise display means supporting a plurality of display views, wherein a said view comprises a list of reserved connections, and for each said displayed reserved connection; a display of start time of the reserved connection. The display means may display an end time of the reserved connection.
The network management apparatus may comprise display means for displaying a plurality of display views of reserved connections, wherein for each said displayed reserved connection there is displayed data describing parameters of said reserved connection wherein said parameters are selected from the set a traffic type; a link data capacity; a route data capacity; a peak bitrate; an average bitrate; an estimated cell loss; a priority rating of a said connection.
The network management apparatus may comprise display means supporting a plurality of display views, wherein a said view comprises a bar chart display displaying data representing a plurality of links on a first axis, and displaying data representing time on a second axis; wherein said data representing a plurality of said links comprises data representing utilization of said links.
The network management apparatus may comprise display means supporting a display view, wherein data describing utilization is color coded according to an amount of said utilization.
The network management may comprise display means supporting a plurality of display views, wherein a said display view comprises:
a display of data describing a plurality of services arranged along a first axis, and data describing time on a second axis;
wherein said display of said data describing said services comprises a plurality of icons representing available time slots specified in a plurality of connection requests; and a plurality of icons representing time durations of reserved connections.
The network management apparatus may comprise display means supporting a plurality of display views, in which an available time slot icon comprises:
an icon representing a start time; and
an icon representing an end time.
The invention includes a network controller adapted to operate the process according to the first aspect.